The processing of photographic material involves a series of steps such as developing, bleaching, fixing, rinsing, and drying. These steps lend themselves to mechanization by conveying strips of photosensitive material sequentially through a series of stations or tanks, each one containing a different processing liquid appropriate to the process step at that station.
Typically, the photosensitive material being processed is immersed in and drawn through the processing liquid in a series of processing tanks. The photosensitive material can be drawn through the processing liquid by pinch rollers, timing belts or other means.
These methods are satisfactory when the processing tanks are of large volume. However, due to the high costs associated with the processing liquids, it is desirable to minimize the amount of processing liquid that is required in the processing of photographic material. Therefore, low volume processing tanks are preferred. When the volume of processing liquid that is required is minimized, any area where solution can be entrapped and carried out of the tank, other than at or on the photosensitive material processing surface, needs to be eliminated or reduced.
U.S. Pat. No. 4,775,873 to Blackman discloses a compactly designed photographic film processing apparatus. The apparatus includes a processing tank in which an upright processing rack is located. An endless timing belt is located in the rack to drive an aperatured leader card which in turn is connected to the photographic film. The tank walls and integral portions of the rack opposite the tank walls define the vertical sides of the processing channel. The tank also has integral portions to define a guide slot for the timing belt.
This photographic film processor design has inherent disadvantages. The use of a timing belt requires a larger volume tank, and therefore requires a greater volume of processing liquid, because clearance must be provided for the timing belt. Further, the timing belt will entrap and carry out of the tank processing solution, thereby further increasing the volume of processing solution required. The object of the present invention is to provide an apparatus for processing photosensitive material that minimizes the volume of processing liquid required.